This invention relates to a control computer connected to a storage apparatus and a search computer, and more particularly to a technology of controlling access to information resources.
Higher performance and a lower price of a computer system achieved in recent years now allow the computer system to be used for various purposes. Accordingly, the amount of information resources saved in the computer system has been significantly increasing. To increase availability of information resources stored in the computer system, an importance of a technology of improving access performance with respect to information resources has been increasing.
Recently, a technology of searching an information resource among a huge amount of information resources has been widely used. According to the search technology, a search server manages index information of the information resources stored in the computer system. A user designates search conditions such as a search keyword regarding information resources to be obtained. Then, a client machine transmits a search request containing the designated search conditions to the search server. Upon reception of the search request from the client machine, the search server creates a search result list with respect to the received search request based on the index information. The search server returns the created search result list to the client machine. The search result list contains identifiers of the searched information resources, access destination information and the like. The client machine receives the search result list. Then, the client machine accesses the information resources by using the access destination information contained in the received search result list.
A cache control technology of speeding-up access to the information resources has been known. According to the cache control technology, an information resource management server prefetches information resources identified by the identifiers contained in the search results list in a cache memory. Thus, a cache hit rate is increased. The cache hit rate indicates a probability that information resources requested to be accessed are stored in the cache memory.
For example, the cache control technology is disclosed in JP 2006-85565 A. According to the technology disclosed in JP 2006-85565 A, an information resource management server creates a predicted download list based on a search log and a download log. Then, the information resource management server updates information resources stored in the cache memory based on the created download list.